To improve fuel economy, some types of vehicles such as hybrid electric vehicles (HEVs) may provide regenerative (regen) braking, in which kinetic energy is converted by an electric machine into storable energy during braking and then made available for propulsion. Regenerative braking is one of the enablers of hybrid vehicle technologies. It has been found that a 15%˜30% fuel economy improvement over a non-regenerative braking-capable vehicle can be achieved using regenerative braking.
An anti-lock braking system (ABS) an automobile safety system that allows the wheels on a motor vehicle to maintain traction with a road surface according to driver inputs during braking. Anti-lock braking prevents the wheels of the vehicle from locking up (ceasing rotation) to avoid uncontrolled skidding. Anti-lock braking generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces. On loose surfaces such as gravel or snow-covered pavement, anti-lock braking can significantly increase braking distance although still improving vehicle control.
A system and method for applying regenerative braking during anti-lock friction braking on surfaces which are characterized by a high friction coefficient may be desirable for some applications.